An Apendix to the Directions for Seaman, bound for far voyages. Of the judgment of some of the English Astronomer, touching the difference between the learned men, about an Observation made of the first of the two late Comets. Of a Correspondency, to be procured, for the finding out of the True distance of the Sun and Moon from the Earth. Of an Observations not long since made in England of Saturn. An Account of some Mercurial Observations, made with a Barometer, and their Results. Some Observations of Vipers, made by an Italian Philosopher.

An Appendix to the Directions for Seamen bound for far Voyages.

Hereas it may be of good use, both Naval and Philosophical, to know, both how to found depths of the sea without a Line, and to fetch up water from any depth of the same; the following waies have been contrived by Mr. Hook to perform both; (which should have been added to the lately printed Directions for Seamen, if then could have been conveniently done.)

First, for the founding of depths without a Cord, consider Figure 1, and accordingly take a Globe of Firr, or Maple, or other light Wood, as A: let it be well secured by Vernish, Pitch, or other wile from imbibing water; then take a piece of Lead or Stone, D, considerably heavier; then will sink the Globe: let there be a long Wire-staple B, in the Ball A, and a springing Wire C, with a bended end F, and into the said staple, prefix in with your fingers the springing Wire on the bended end: and on it hang the weight D, by its ring E, and so let Globe and all sink gently into the water, in the posture represented in the first Figure, to the bottom, where the weight D touching first, is there by stopt, but the Ball, being by the Impetus, it acquired in descending, carried downwards a little after the weight is stopt, suffers the springing wire to fly back, and thereby sets it self at liberty to reascend. And, by observing the time of the Ball's stay under water (which may be done by a Watch, having minuts and seconds or by a good Minut-glass, or best of all, by a Pendulum vibrating seconds) you will by this way, with the help of some Tables, come to know any depth of the sea.

Note, that care must be had of proportioning the weight and shape of the Lead, to the bulk, weight, and figure of the Globe, after such a manner, as upon experience shall be found most convenient.

In some of the Tryals already made with this Instrument the Globe being of Maple-wood, well covered with Pitch to hinder soaking in, was 51316{\displaystyle \scriptstyle {\frac {13}{16}}} inches in diameter, and weighed 212{\displaystyle \scriptstyle {\frac {1}{2}}} pounds; the Lead of 412{\displaystyle \scriptstyle {\frac {1}{2}}} pounds weight, was of a Conical figure, 11. inches long, with the sharper end downwards; 1916{\displaystyle \scriptstyle {\frac {9}{16}}} inches at the top, and 116{\displaystyle \scriptstyle {\frac {1}{16}}} at the the bottom in diameter. And in those Experiments made in the Thames, in the depth of 19. foot water, there passed between the Immersion and Emersion of the Globe, 6. seconds of an hour; and in the depth of 10. foot water; there passed 312{\displaystyle \scriptstyle {\frac {1}{2}}} seconds or thereabout: From many of which kind of Experiments, it will likely not be hard, to find out a method to calculate, what depth is to be concluded from any other time of the like Globes stay under water.

In the same Tryals, made with this Instrument in the said River of Thames, it has been found, that there is no difference in time, between the submersions of the Ball at the greatest depth, when it rose two Wherries length from the place where it was let fall (being carried by the Current of the Tide) and when it rose within a yard or so of the same place where it was let down.

The other Instrument, for Fetching up water from the depth of the sea, is (as appears by Figure 2.) a square woodden Bucket C, whose bottoms EE, are so contrived, that as the weight A, finks the Iron B, (to which the Bucket C, is fastned by two handles DD, on the ends of which are the moveable bottoms or Valves EE,) and thereby draws down the Bucket; the resistance of the water keeps up the Bucket in the posture C; whereby the water hath, all the while it is descending, a clear passage through; whereas, as soon as the Bucket is pulled upwards by the Line F, the resistance of the water to that motion beats the Bucket downward, and keeps it in the posture G, whereby the Included water is preserved from getting out, and the Ambient water kept from getting in.

By the advantage of which Vessel; it may be known, whether sea water be Salter at and towards the bottom, then at or near the top: Likewise, whether in some places of the sea, any sweet water is to be found at the bottom; the Affirmative whereof is to be met with in the East India Voyages of the industrious John Hugh Van Linschoten, who page 16 of that Book, as 'tis Englished, records, that in the Persian Gulph, about the Island Barem, or Babarem, they fetch up with certain Vessels (which he describes not) water out of the sea, from under the salt-water, four or five fathom deep, as sweet, as any Fountain water.

Of the Judgement of some of the English Astronomers, touching the difference between two learned men, about an Observation made of the First of the two late Comets.

Whereas notice has been taken in Num. 6. of these Transactions, that there was some difference between those two deservedly celebrated Philosophers, Monsieur Hevelius and Monsieur Auzout, concerning an Observation, made by the former of them, on the, 818{\displaystyle \scriptstyle {\frac {8}{18}}} of February 1665. & that thereupon some Eminent English Astronomers, considering the importance of the dispute, had undertaken the examination thereof; it will, 'tis conceived, not be unacceptable to such, as saw those Papers, to be informed, what has been done and discerned by them in that matter. They having therefore compared the Printed Writings of the two Dissenters, and withall consulted the observations made with Telescopes at home, by some of the most intelligent Astronomers amongst them, who have attentively observed the Position of that Comet to the Telescopical starts, that lay in its way; Do thereupon Joyntly conclude, that, whatever that Appearance was, which By Telescopical Stars are understoof such, as are not seen, but by the help of a Telescope. was seen near the First star of Aries, by Monsieur Hevelius (the truth of whose relation concerning the same, they do in no wise question) the said Comet did not come neer that Star in the left Ear of Aries, where the said M. Hevelius supposes it to have passed, but took its course neer the Bright Star in its Left Horn, according to Bayers Tables. And since that the Observations of judicious both French, ItaIian, &c. Dutch Astronomers (as many of them, as are come to the know. ledgeof the English) do in the main fully agree with theirs, they do not at all doubt, but that, there being such an unanimous consent in what has Been just now declared, & the Controversie being about Matter of fact, wherein Authority, Number, and Reputation must cast the Ballabce, Mons. Hevelius, who is as well known for his ingenuity, as Learning, will joyn and acquiesce in that sentiment.

Of a Correspondency, to be procured, for the Finding out the True distance of the Sun and Moon from the Earth, by the Paralax, observed under (or neer) the same Meridian.

Seeing that the knowledge of this distance may prove of important Life, for the Perfecting of Astronomy, and for the better establishing the doctrine of Refractions; it is in the thoughts of some very curious Persons in England, for the finding out the same, to settle a Correspondency with some others abroad that are understanding in Astronomical matters, and live in places far distant in Latitude, and under (or near) the same Meridian.

To perform which, the following Method is proposed to be observed; viz. That at certain times agreed on by two Observatours, making use of Telescopes, large, good and well fitted for this purpose, by a measuring rod, placed within the Eye-glass at a convenient distance, that it may be distinctly. seen, and serve for measuring small distances by minuts and seconds (which is easie enough in large Telescopes) that, I say, each of such observers, thus furnish't, shall observe the visible way of the Moon among the Fixt stars, (by taking her exact distance from any Fixt starr, that lyes in or very near her way, together with the exact time of her so appearing) and the then apparent Diameter of her Disk; continuing these Observations every time for two or three hours, that so, if possible, two exact observations of her Apparent place among, the Fixt stars being made, at two places thus distant in Latitude, and as near as may be under the same Meridian, by these Observatory concurring at the same time, her true and exact distance may be hence collected, not onely for that time but at all other times, by any single Observator's viewing her with a Telescope, and measuring exactly her Apparent Diameter. It were likewise desirable, that as often as there happens any considerable Eclipse of the Sun, that this also might be observed by them, noting therein the exact measure of the greatest Obscuration compared with the then Apparent Diameter of his Disk. For by this means, after the distance of the Moon hath been exactly found, the distance of the Sun will easily be deduced.

As for the time, fittest for making Observations of the Moon, that will be, when she is about a Quarter or somewhat less illuminated, because then her light is not so bright, but that with a good Telescope she may be observ'd to pass close by, and sometimes over several Fixt stars; which is about four or five days before or after her Change: Or else at any other time, when the Moon passes near or over some of the bigger fort of Fixt stars, such as of the first or second Magnitude; which may be easily calculated and foreseen: Or best of all when there is any Total Eclipse of the Moon; for then the smallest Telescopical stars may be seen close adjoyning to the very of the Moon. Of all which particulars the two Correspondents are to agree, as soon as he, that is to joyn abroad, shall be found out; whereupon they are mutually to communicate to each other, what they shall have thus observed in each place.

Of an Observation, not long since made in England, of Saturn.

This Observation was made by Mr. William Ball, accompanied by his brother, Dr. Ball, October 13. 1665. at fix of the Clock, at Mainhead near Exeter in Devonshire, with a very good Telescope near 38 Foot long, and a double Eye-glass, as the observer himself takes notice, adding, that he never saw that Planet more distinct. The observation is represented by Figure 3. concerning which, the Author saith in his letter to a friend, as follows; This appear'd to me the present figure of Saturn, somewhat otherwise, than I expected, thinking it would have been decreasing, but I found it full as ever, and a little hollow above and below. Whereupon the Person, to whom notice was sent hereof, examining this shape, hath by Letters desired the worthy Author of the Systeme of this Planet, that he would now attentively consider the present Figure of his Anses or Ring see whether the appearance be to him, as in this Figure, and consequently whether he there meets with nothing that may make him think, that it is not one body of a Circular Figure, that embraces his Diske, but two.

And to the end that other Curious men, in other places might be engaged, to joyn their Observations with him, to see, whether they can find the like appearance to that, represented here, especially such Notches or Hollownesses, as at A and B, it was thought fit to insert here the newly related Account.

A Relation of some Mercurial Observations, and their Results.

Modern Pbilosophers, to avoyd Circumlocutions, call that Instrument, wherein a Cylinder of Ouicksilver, of between 28 and 31 Inches in Altitude, is kept suspended after the manner of the Torricelian Experiment; a Barometer or Baroscope, first made publick by that Noble Searcher of Nature. Mr. Boyle, and imployed by Him and others, to detect all the minut variations in the Pressure and weight of the Air. For the more

curious and nice distinguishing of which small changes, Mr. Hook in the Preface to his Micrography, has described such an Instrument with a Wheel, contrived by himself; and, by these two last years trials of it, constantly found most exact for that purpose: which being so accurate, and not difficult to be made, it were desirable, that those who have a Genius and opportunities of making Observations of this kind, would furnish themselves with such of these Instruments, as were exactly made and adjusted according to the Method, delivered in the newly mentioned place.

To say something of the Observations, made by this Instrument, and withal to excite studious Naturalists to a sedulous prosecution of the same, the Reader may first take notice, that the lately named Mr. Boyle hath (as himself not long since did intimate to the Author of these Tracts) already made divers Observations of this kind in the year 1659. and 1660. before any others were publick, or by him so much as heard of; though he has hitherto forborn to divulge them, because of some other Papers (in whose Company they were to appear) which being hindred by other studies and employments, he hath not as yet finished.

Next, that, besides several others, who, since have had the curiosity of making such observations, the Worthy and Inquisitive Dr. John Beal, is doing his part with much assiduity (of which he hath by several Letters acquainted his Friends in London) both by observing himself, and by procuring many Correspondents in several places in England for the same purpose; judging it of great importance, that Observations of this kind be made in arts somewhat distant from one another, that so from many of those, accurately made and then compared, it may be discovered, whether the Aire gravitates more in the parts of the Earth lying more East or West, North or South? whether on such as lie neerer to the Sea, or further up into the Mainland? in hotter or colder weather? whether in high Winds or Calms? whether in wet weather or dry? whether most when a North, or when a South, when an East or a West wind blows? and whether it keeps the same seasons of Changes? and whether the seasons and changes of the Air and Weather can be thereby discover'd, and the now hidden causes of many other Phænomena detected?

The said Doctor is so much pleased wish the discovery already made by the help of this Instruments, that he thinks it to be one of the most wonderful that ever was in the World, if we speak of strangeness, and just wonder, and of Philosophical importance, separate from the interest of lucre. For (saith he, in one of his Letters) who could ever expect, that we men should find an Art, to weigh all the Air that hangs over our heads, in all the Changes of it, and, as it were, to weigh, and to distinguish by weight, the Winds and the Clouds? Or, who did believe, that by palpable evidence we should be able to prove, the serenest? Air to be most heavy, and the thickest Air, and when darkest Clouds hang neerest to us, ready to dissolve, or dropping, then to be lightest. And though (so he goes on) we cannot yet reach to all the Uses and Applications of it; yet we should be entertain'd for a while, by the truly Honourable Mr. Boyle, as the leading person herein, upon the delight and wonder. The Magnet was known tranny hundreds of years before it was applied to Find out New Worlds. To me (saith he) tis a wonderful delight, that I have alwaies in my Study before my eye such a Curious Ballance.

Having thus in General expressed his thoughts about this Invention, and the singular pleasure, he takes in the Observations made therewith, he descends to particulars, and in several Letters communicates them to his Correspondent, as follows:

1. My Wheel-barometer I could never fill so exactly with Mercury, as to exclude all Airs and therefore I trust more The Exclusion of all Air is here necessary, because Air being subject to the operation of Heat and Cold, if any of it remain in the Barometer, it will cause it to vary from the Wing the true Pressure of the Air. to a Mercurial Cane, and take all my Notes from it, This Cane is but 35. Inches long, of a very slender Cavity, and thick Glass. This may easily be conveyed to any place, for Trials. The Vessel for the stagnating Mercury, into which the said Cane is immersed, is about two Inches wide. The Mercury so well fill'd, that for some daies it would not subside, but hung to the top of the Glass cane. I keep it in a Closet pretty close, 9. foot high, 8. foot broad, 15. foot long; neer a Window. This I note, because possibly the closeness of the room may hinder, that it gives not the full of all Changes, as it might in a more passable Air.

2.In all my Observations from May 28. 1664 to this present (December 9. 1665.) the Quicksilver never ascended but very little above 30¼ Inches.

3. It ascended very seldom so high (videl. to 30¼ Inches) chiefly in Decemb. 13. 1664. the weather being fickle-fair, Evening.

4. I find by my Calender of June 22. 1664. at 5. in the Morning, in a time of long setled fair weather, that the Mercury had ascended about half an Inch higher then 30: but I fear some mistake, because I then took no impression of wonder at it; yet for 3. or 4. daies, at that time it continued high, in well. setled, fair and warm weather; most part above 30. Inches. So that I may note, the Mercury to rise as high in the hottest Summer, as in the coldest Winter-weather.

5. Yet surely I have noted it ascend a little higher for the Coldness of the Weather; and very frequently, both in Winter Perhaps this is from some included Air.and Summer to be higher in the cold Mornings and evenings, then in the warmer Mid-day.

6. Generally in setled and fair weather both of Winter and Summer, the Mercury is higher, than a little before or after, or in Rainy weather.

7. Again, generally it descended lower after Rain, than it was before Rain.

8. Generally also it falls in great winds; and somewhat it It seems these were Eastern winds. seem'd to sink, when I open'd a wide door to it, to let in stormy yet I have found it to continue very high in a long stormy wind of 3. or 4. daies.

9. Again, generally it is higher in an East and North-wind. (Cœteris paribus) than in a South and West-wind.

10. I tryed several times, by strong fumes and thick smoaks to alter the Air in my Closet; but 1 cannot affirm, that the Mercury yielded any more, then might be expected from some increase of heat. Such as have exact Wheel-Barometers, may try whether Odors or Fumes do alleviate the Air.

11. In this Closet I have not in all this time found the extreamest changes of the Quicksilver to amount to more, than to 234{\displaystyle \scriptstyle {\frac {3}{4}}}, or to 278{\displaystyle \scriptstyle {\frac {7}{8}}}, inches, at most.

12. Very often I have found great changes in the Air, without any perceptible change in the Barometer; as in the dewy nights, when the moisture descends in a great quantity, and the thickness sometimes seems to hide the Stars from us: In the days foregoing and following, the Vapors have been drawn up so Invisibly, that the Air and Sky seem'd very clear all day long. This I account a great change between ascending and descending Dews and Vapors (which import Levity and Weight,) and between thick Air and clear Air; which changes do sometimes continue in the Alternative course of day and night, for a week or fortnight together, and yet the Baroscope holding the same.

13. Sometimes (I say not often) the Baroscope yields not to other very great changes of the Air. As lately (December 18.) an extraordinary bright and clear day; and the next following quite darkned, some Rain and Snow falling; but the Mercury the same: so in high winds and calms the same.

14. I do conceive, that such as converse much Sub dio, and walk much abroad, may find many, particulars much more exactly, then I, who have no leisure for it, can undertake. To instance in one of many, December. 16. last, was a clear cold day, very sharp and strong East wind; the Mercury very near 30. inches high, about three in the afternoon, I saw a large black cloud, drawing near us from the East and South-East, with the East-wind. The Mercury changed not that day nor the day following, the Stars and most of the sky were very bright and clear till Nine of the Clock; and then suddenly all the sky was darkned, yet no change of weather happened; December 17. the frost held, and 'twas a clear day, till about two of the clock in the afternoon; and then many thick clouds appear'd low in the West, yet no change of the weather here; the Wind, Frost, and Quick-siver, the same, December 18. the Mercury fell almost 14{\displaystyle \scriptstyle {\frac {1}{4}}} of an inch, and the sky and Air so clear and bright and cold with an East-wind, that I wondred what could cause the Mercury to descend. I Expected, it should have ascended, as usually it does in such clear skys. Casually I sent my servant abroad, and he discovered the remote Hills, about 20. miles off, cover'd with snow, This seem'd to manifest, that the Air, being discharged of the clouds by snow, became lighter.

15. I have seldom seen the change to be very great, at any one time. For, though I do not now take a deliberate view of my Notes, yet I wonder'd once to see, that in one day it subsided about ¾ of an inch.

16. Of late I have altered my Method upon the Barometer, observing it, as it is before my Eyes, all day long, and much of the night, being watchful for the moments of every particular change, to examine, what cause in the Air and Heavens may appear for such changes. And now my wonder is, to see, how flow it is, it holding most between the nine and twentieth and thirtieth inch of late.

17. I must now (January 13 16656{\displaystyle \scriptstyle 166{\frac {5}{6}}}) tell you, that the Mercury stands at this time (as it did also yesterday) a quarter above 3O. inches; yet both days very dark and cloudy, sometimes very thick and misty Air; which seldom falls out. For, for the most part, I see it higher in clearest setled weather, than in such cloudy and misty Foggs. This thick Air and darkness hath lasted above a week; lately more Cold, and East and North-East wind.

Thus far the Notes of this Observing Divine; of which Mr. Boyle, to whom they were also communicated, entertains these thoughts, that they seem to him very faithfully made, and do for the main, agree well enough with his observations, as far as he remembers, not having them, it seems, at that time, when he wrote this, at hand; and though it be wished by him, This seem to be wished, because the motion of the Mercury may be more free in a wider Cane. that the Observes Glass-Cane had been somewhat bigger; yet his diligence in fitting it so carefully, or rather so skilfully, as is above mentioned, is much by him commended.

Some Observations of Vipers.

A curious Italian, called Francesco Redi, having lately had an opportunity, by the great number of Vipers, brought to the Grand Duke of Toscany for the composing of Therias or Treacle, to examine what is vulgarly deliverer and believed concerning the Poyson of those Creatures, hath, (according to the account, given of it in the French Journal des Scavans, printed January 4. 16656{\displaystyle \scriptstyle 166{\frac {5}{6}}}) performed his undertaking with much exactness, and publish't in an Italian tract, not yet come into England, these Observations.

1. He hath observed, that the poyson of Vipers is neither in their Teeth, nor in their Tayle, nor in their Gall; but in the two Vesicles or Bladders, which cover their teeth, and which coming to be compressed, when the Vipers bite, do emit a certain yellowish Liquor, that runs along the teeth and poysons the wound. Whereof he gives this proof; that he hath rub'd the wounds of many Animals with the Gall of Vipers, and pricked them with their Teeth, and yet no considerable ill accident follow'd upon it, but that as often as he rubbed the wounds with the said yellow Liquor, not one of them escaped.

2. Whereas commonly it hath hitherto been believed, that the poyson of Vipers being swallowed, was present death; this Author, after many reiterated Experiments, is said to have observed, that in Vipers there is neither Humour, nor Excrescent, nor any part, not the Gall it self; that, being taken into the Body, kills. And he assures', that he hath seen men eat, and hath often made Bruit Animals swallow all that is esteem'd most poysonous in a Viper, yet without the least mischief to them. Whence he shews, that it needs not so much to be wondred at, that certain Empiricks swallow the juyce of the most venomous Animals without receiving any harm thereby; adding, that, which is adscribed to the vertue of their Antidote, ought to be attributed to the nature of those kinds of Poysons, which are no poysons, when they are swallow'd, (for which Doctrine he also alledges Celsus) but onely when they are put into wounds. Which also has been-noted by Lucan, who introduces Cato thus speaking;

And what also some Authors have affirm'd, videl. That it is mortal, to eat of the Flesh of creatures killed by Vipers; or to drink of the Wine wherein Vipers have been drowned; or to flick the wounds that have been made by them, is by this Authour observed to be wide of truth. For he assures, that many persons have eaten Pullers and Pigeons, bitten by Vipers, without finding any alteration from it in their health. On the contrary, he declares, That it is a soveraign Remedy against the biting of Vipers, to suck the wound, alledging an Experiment, made upon a Dog, which he caused to be bitten by a Viper at the nose, who by licking his own wound saved his life. Which he confirms by the example of those people, celebrated in History by the name of Marsi and Psilli, whole Employment it was, to heal those, that had been bitten by Serpents, by sucking their wounds.

3. He adds, that although Galen and many modern Physitians do affirm, that there is nothing, which causeth so much thirst, as Vipers-flesh, yet he hath experimented the contrary and known divers persons, who did eat the flesh of Vipers at all their meals, and yet did assure him, they never were less dry, then when they observed that kind of Diet.

4 As for the Salt of Vipers, whereof some Chymists have so great esteem, he saith, that it hath no Purging vertue at all in it; adding that even of All Salts, none hath more vertue than another, as he pretends to have shew'd in an other Book of his, De natura salium; which also hath not been yet transmitted into these parts.

5. He denies, what Aristotle assures, and what Galen saith to have often tryed, that the Spittle of a Fasting person kills Vipers, and he laughs at many other particulars, that have been delivered concerning the Antipathy of Vipers unto certain things; and their manner of Conception and Generation, and several other properties, commonly ascribed to them; which the alledged French Author affirms to be refuted by so many experiments made by this Italian Philosopher, that it seems to him, there is no place left for clouting, after so authentick a testimony.

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The Reader of these Transactions is desired to correct these Errata in Number 8.viz. page. 132. line, penult, read Wine for Lime, and page 133. line. 10. read Thresher for Trespher, as some Copies have it; and page 136. line ult. read purifie for putrifie.

LONDON

Printed for John Martyn and James Allestree, Printers to the Royal Society. 1666.